Effect of cobalt on γ′ coarsening behavior of Ni-base powder metallurgy superalloy

• Published in: Journal of alloys and compounds 2022-11, Vol.921, p.166057, Article 166057
• Main Authors: Ye, Xianjue, Zhou, Dingmao, Yang, Biaobiao, Wang, Fenglin, Liu, Jiantao, Li, Yunping
• Format: Article
• Language: English
• Subjects: Coarsening; Exposure; Gamma prime; Gamma-prime phase (crystals); Interfacial energy; Morphology; Nickel base alloys; Powder metallurgy; Superalloy; Superalloys; Thermal exposure
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2022.166057

Influence of Co on the coarsening behavior of γ’ phase in Ni-base superalloy was investigated. Long term thermal exposure at 750 °C and 850 °C were carried out on alloys with Co contents of 10, 20, 25 wt%. The coarsening rates of γ’ phase were observed to decrease gradually with increasing Co content ascribed to the lower interfacial energy between γ and γ’ in high Co content alloy. In addition, γ′ phase morphology after thermal exposure at 750 °C shows the cubic shape in low Co content alloy and spherical shape in the high Co content alloy. γ′ phase morphology evolution during thermal exposure is found to be highly related to the γ/γ′ misfit. •Influence of Co on coarsening behavior of γ’ in superalloy was investigated.•The coarsening rate of γ’ decreases gradually with increasing Co content.•The lower γ’ coarsening rate is ascribed to lower γ/γ’ interfacial energy by Co.•Morphology evolution of γ′ is highly related to the misfit of γ/γ.